Drum-type washing machine with water level sensing unit

ABSTRACT

A drum-type washing machine having a water level sensing unit prevents a water level sensing hose from being damaged or broken, which allows a water level to be precisely detected. Further, the drum-type washing machine prevents the water level sensing hose from being clogged with impurities. The drum-type washing machine includes a water tub to contain water therein, and the water level sensing unit to detect a level of the water contained in the water tub. The water level sensing unit includes the water level sensing hose to communicate with the water tub, and a water level sensor to detect a pressure in the water level sensing hose and the level of the water contained in the water tub. The water level sensing hose is mounted to be spaced apart from the water tub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2003-79253, filed on Nov. 10, 2003 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates, in general, to drum-type washing machines and, more particularly, to a drum-type washing machine which prevents a water level sensing unit thereof from being damaged or broken due to vibration, in addition to preventing the water level sensing unit from being clogged with impurities, such as lint.

2. Description of the Related Art

Generally, a drum-type washing machine includes a cabinet, a door, a water tub, a rotary tub, and a drive motor. The door is mounted to a surface of the cabinet to be open and closed. The water tub is located in the cabinet, and is a shape of a drum which opens toward the door. The rotary tub is rotatably installed in the water tub. The drive motor drives the rotary tub.

Laundry is located in the rotary tub to be washed, and wash water is fed into the water tub. A water level sensing unit is installed at a predetermined position of the water tub to detect a level of water fed into the water tub, thus allowing an appropriate amount of wash water to be fed into the water tub.

A conventional water level sensing unit of a drum-type washing machine is disclosed in Korean Patent Laid-Open Publication No. 1999-0051584. According to this Publication, the water level sensing unit includes a water level sensing hose. The water level sensing hose is coupled to a predetermined portion of the water tub. However, the water tub suffers violent vibration due to an operation of the drive motor. Thus, the water level sensing hose coupled to the water tub may be damaged or broken, due to the vibration of the water tub.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a drum-type washing machine having a water level sensing unit, which prevents a water level sensing hose from being damaged or broken due to vibration, and from being clogged with impurities, in addition to being capable of precisely detecting a water level.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

The foregoing and/or other aspects are achieved by providing a drum-type washing machine comprising a water tub to contain water therein, a water level sensing unit to detect a level of the water contained in the water tub, and a drain pump to drain the water from the water tub, wherein the water level sensing unit is coupled to a predetermined portion of the drain pump.

The water level sensing unit comprises a water level sensing hose coupled to the predetermined portion of the drain pump to communicate with the water tub, and a water level sensor to detect a pressure in the water level sensing hose, and the level of the water contained in the water tub. The water level sensing hose is coupled to a suction pipe of the drain pump.

Further, the water level sensor is installed on an upper end of the water level sensing hose, and the water level sensing hose comprises a large-diameter part provided on a lower portion of the water level sensing hose, and a small-diameter part provided between the large-diameter part of the water level sensing hose and the water level sensor. The large-diameter part comprises a length of approximately 10 cm or more.

It is another aspect of the present invention to provide a drum-type washing machine comprising a cabinet, a water tub set in the cabinet and containing water therein, a holding unit mounted to a predetermined portion of the cabinet and communicating with the water tub, and a water level sensing unit to detect a level of the water contained in the water tub. The water level sensing unit comprises a water level sensing hose coupled to a predetermined portion of the holding unit to communicate with the water tub, and a water level sensor to detect a pressure in the water level sensing hose and the level of the water contained in the water tub.

The holding unit comprises a drain pump to drain the water from the water tub.

The water level sensing hose is coupled to a suction pipe of the drain pump.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a side sectional view of a drum-type washing machine, according to an embodiment of the present invention;

FIG. 2 is a perspective view illustrating a water level sensing unit coupled to a drain pump of the drum-type washing machine of FIG. 1; and

FIG. 3 is a side view of a water level sensing unit of the drum-type washing machine of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the figures.

In FIG. 1, a drum-type washing machine 100 according to an embodiment comprises a cabinet 10, a door 11, a water tub 20, a rotary tub 21, and a drive motor 22. The door 11 is mounted to a surface of the cabinet 10 to be open and closed. The water tub 20 is located in the cabinet 10, and comprises a drum shape, which is open toward the door 11. The rotary tub 21 is rotatably installed in the water tub 20. The drive motor 22 drives the rotary tub 21.

The rotary tub comprises a lifter 25 mounted to an inner surface of a sidewall of the rotary tub 21 to move laundry located on a bottom of the rotary tub 21 upward, when the rotary tub 21 rotates. The rotary tub further comprises a plurality of perforations 26 on the sidewall of the rotary tub 21 to feed wash water from the water tub 20 into the rotary tub 21.

The water tub 20 and the rotary tub 21 are concentrically located in the cabinet 10 along a same central axis. The drive motor 22 is provided on the central axis.

The drum-type washing machine, further comprises a water supply pipe 30 interiorly provided on an upper portion of the cabinet 10 to supply water to the water tub 20 and a detergent container 33 provided at a predetermined position above the door 11 coupled to the water supply pipe 30.

The water tub further comprises a water supply hole 23 on a top wall of the water tub 20 wherein an end of the water supply pipe 30 is coupled to the water supply hole 23. The water tub further comprises a water drain hole 24 formed on a bottom of the water tub 20 to drain the water from the water tub 20 through the water drain hole 24.

A drain pump 40 is mounted to a bottom of the cabinet 10 to drain the water from the water tub 20. A suction pipe 41 is provided on a predetermined portion of the drain pump 40 to draw the water from the water tub 20 to the drain pump 40, and a discharging pipe 42 is provided on a predetermined portion of the drain pump 40 to discharge the water from the drain pump 40. A first drain pipe 31 connects the water drain hole 24 of the water tub 20 to the suction pipe 41. A second drain pipe 32 is connected, at a first end thereof, to the discharging pipe 42, while extending, at a second end thereof, to an outside of the cabinet 10.

The drum-type washing machine 100 further comprises a water level sensing unit 50 to detect a level of the water contained in the water tub 20. The water level sensing unit 50 comprises a water level sensing hose 51 and a water level sensor 54. The water level sensing hose 51 is coupled, at a lower end thereof, to the suction pipe 41 of the drain pump 40. The water level sensor 54 is installed on an upper end of the water level sensing hose 51 to detect air pressure in the water level sensing hose 51. The water level sensing hose 51 comprises a small-diameter part 52 and a large-diameter part 53. On an upper end of the small-diameter part 52 is installed the water level sensor 54. The large-diameter part 53 connects to a lower end of the small-diameter part 52.

The operation of the drum-type washing machine 100 having the water level sensing unit 50 according to an embodiment of the present invention will be described in the following.

First, laundry to be washed is located in the rotary tub 21 which is rotated by the drive motor 22. When the rotary tub 21 rotates, the laundry located on the bottom of the rotary tub 21 is upwardly moved by the lifter 25 which is mounted to the inner surface of the sidewall of the rotary tub 21, and then drops to the bottom of the rotary tub 21 due to gravity. While the laundry is moved upwardly and drops to the bottom of the rotary tub 21, an impact force and friction between articles of laundry are generated, thus washing the laundry.

Wash water is supplied through the water supply pipe 30 to the water tub 20. Since the water supply pipe 30 is coupled to the detergent container 33, a detergent is fed into the water tub 20 together with the water while being dissolved in the water. In order to supply an appropriate amount of water to the water tub 20, the water level sensing unit 50 detects the level of the water contained in the rotary tub 21.

The large-diameter part 53 provided on the lower end of the water level sensing hose 51 of the water level sensing unit 50, communicates with a lower portion of the water tub 20 through the suction pipe 41 of the drain pump 40 and the first drain pipe 31. Therefore, as the water is supplied to the water tub 20, a water level of the large-diameter part 53 increases. When the water level of the large-diameter part 53 gradually increases, air in the water level sensing hose 51 is compressed. Thus, pressure in the water level sensing hose 51 increases. The variance of pressure is detected by the water level sensor 54, therefore the level of the water contained in the water tub 20 is detected.

According to the present invention, the lower end of the water level sensing hose 51 is coupled to the suction pipe 41 of the drain pump 40 which is mounted to the cabinet 10, differently from a conventional water level sensing hose of which a lower end is coupled to a water tub. Thus, the water level sensing hose 51 is not affected by the vibration generated during an operation of the drive motor 22.

Since the water level sensing hose 51 comprises the large-diameter part 53 at the lower portion thereof, the water level sensing hose 51 of the present invention comprises a larger variance of pressure than the conventional water level sensing hose having a constant diameter, in response to a same variance of a water level, to allow the water level sensor 54 to precisely detect the water level.

Since the pressure of the compressed air acts on a water surface of the large-diameter part 53, the water surface of the large-diameter part 53 is lower than a water surface of the water tub 20 on which the atmospheric pressure acts. Since the large-diameter part 53 comprises a predetermined length sufficient to prevent the water of the large-diameter part 53 from reaching the small-diameter part 52 as the water level of the water tub 20 reaches a maximum level, impurities, such as lint, do not clog the small-diameter part 52, thus preventing malfunction of the water level sensing unit 50. The large-diameter part 53 comprises a length of approximately 10 cm or more.

As is apparent from the above description, the present invention provides a drum-type washing machine having a water level sensing unit. According to the present invention, a water level sensing hose of the water level sensing unit is coupled to a predetermined portion of a drain pump mounted to a cabinet, to prevent the water level sensing hose from being damaged or broken due to vibration. Further, the water level sensing hose comprises a large-diameter part at a lower portion thereof, to allow a water level to be precisely detected, and to prevent the water level sensing hose from being clogged with impurities and thereby preventing malfunction of the water level sensing unit.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A drum-type washing machine, comprising: a water tub to contain water therein; a water level sensing unit to detect a level of the water contained in the water tub; and a drain pump to drain the water from the water tub, wherein the water level sensing unit is coupled to a predetermined portion of the drain pump.
 2. The drum-type washing machine of claim 1, wherein the water level sensing unit comprises: a water level sensing hose coupled to the predetermined portion of the drain pump to communicate with the water tub; and a water level sensor to detect a pressure in the water level sensing hose and the level of the water contained in the water tub.
 3. The drum-type washing machine of claim 2, wherein the drain pump comprising a suction pipe, and the water level sensing hose is coupled to the suction pipe of the drain pump.
 4. The drum-type washing machine of claim 3, wherein a lower portion of the water level sensing hose comprises a larger diameter than an upper portion of the water level sensing hose.
 5. The drum-type washing machine of claim 4, wherein the water level sensing hose comprises: a large-diameter part provided on the lower portion of the water level sensing hose; and a small-diameter part provided between the large-diameter part of the water level sensing hose and the water level sensor.
 6. The drum-type washing machine of claim 5, wherein the large-diameter part comprises a length of approximately 10 cm or more.
 7. A drum-type washing machine, comprising: a cabinet; a water tub located in the cabinet to contain water therein; a holding unit mounted to a predetermined portion of the cabinet, and communicating with the water tub; and a water level sensing unit to detect a level of the water contained in the water tub and comprising: a water level sensing hose coupled to a predetermined portion of the holding unit to communicate with the water tub; and a water level sensor to detect a pressure in the water level sensing hose and the level of the water contained in the water tub.
 8. The drum-type washing machine of claim 7, wherein the holding unit comprises a drain pump to drain the water from the water tub.
 9. The drum-type washing machine of claim 8, wherein the drain pump comprises a suction pipe, wherein the water level sensing hose is coupled to the suction pipe.
 10. The drum-type washing machine of claim 7, wherein the water level sensing unit is coupled to the predetermined portion of the holding unit to prevent the water level sensing hose from being damaged due to vibration during an operation of the drum-type washing machine.
 11. The drum-type washing machine of claim 9, wherein the drain pump is mounted to a bottom of the cabinet to drain water from the water tub.
 12. The drum-type washing machine of claim 11, further comprising a suction pipe provided on a predetermined portion of the drain pump to draw the water from the water tub to the drain pump, and a discharging pipe provided on a predetermined portion of the drain pump to discharge the water from the drain pump.
 13. The drum-type washing machine of claim 12, further comprising: a first drain pipe which connects the water drain hole of the water tub to the suction pipe; and a second drain pipe connected at a first end thereof to the discharging pipe, and extended at a second end thereof to an outside of the cabinet.
 14. The drum-type washing machine of claim 5, wherein a pressure of compressed air which acts on a water surface of the large-diameter part causes the water surface of the large-diameter part to be lower than a water surface of the water tub.
 15. The drum-type washing machine of claim 14, wherein the large-diameter part comprises a predetermined length to prevent the water of the large-diameter part from reaching the small-diameter part as the water level of the water tub reaches a maximum level, to prevent a malfunction of the water level sensing unit.
 16. The drum-type washing machine of claim 2, wherein the water level sensor is included on an upper end of the water level sensing hose. 